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A state health official said Thursday that the new case is in the Washington metro area, but she did not give an exact location. The first was reported in mid-July in central Maryland.

Kim Mitchell, who tracks West Nile for the state health department, said the most recent case involves a 70-year-old patient suffering from encephalitis, or swelling of the brain, but it has not been determined if the virus is responsible for the encephalitis. The first patient is recovering after suffering feverish symptoms.

Mitchell said it is normal to have one or two cases at this time of year. Nineteen cases were reported last year and 23 the year before. The mosquito-borne disease was first reported in the United States in 1999.